Overview

Brief Summary

Oryza sativa, rice, is a genus of perennial grass in the Poaceae (grass family) that originated in India, Thailand, and southern China, was domesticated and diversified in ancient times, and is now cultivated in wet tropical, semi-tropical, and warm temperate areas around the world for the production of its cereal grain. Rice is one of the two most important cereal crops world for human consumption; the other is wheat, Triticum species. (Corn, Zea mays, is produced in larger amounts, but a sizable portion of it is used for livestock feed and making ethanol for biofuel). Rice is cultivated on an estimated 3% of the world’s agricultural land, and serves as a primary source of calories for over half the world’s population. Rice has also been important as a model system in plant biology, and is the first plant species for which the genome has been fully mapped.

The name “wild rice” may refer to any of the lesser- or non-cultivated species of Oryza, but is generally used to refer to North American species in the genus Zizania.

Oryza sativa is generally an annual grass, although some varieties are perennial. Plants typically grow in a tuft (clump) of upright culms (stems) up to 2 m or more tall, with long, flat leaf blades. The flowers grow on broad, open terminal panicles (branched clusters). The oblong spikelets, which each contain a single flower (that develops into a single kernel of grain), are sparse along the stem rather than forming dense clusters. The harvested kernel, known as a rice paddy, is enveloped in a hull or husk that is removed during milling.

Oryza sativa has hundreds of cultivars with different grain color, size, and shape, as well as environmental tolerances and seasonality—the types are generally categorized as valley rice, upland rice, spring rice, and summer rice. It is generally grown in fields that are flooded for part of the growing season—whether from irrigation (the majority of cultivation), rainfed or floodplain systems--which help reduces competition from other plants, among other benefits; some upland varieties can be grown without flooding, but they account for only 4% of rice cultivated worldwide.

Rice is thought to have been domesticated in India and brought to China by 3,000 B.C. It was cultivated in Babylon and the Middle East by 2,000 years ago, and spread to the Europe during medieval times.

The FAO estimates that the total commercial harvest of rice in 2010 was 672.0 million metric tons, harvested from 153.7 million hectares. China and India were the leading producers, followed by Indonesia, Bangladesh, and Vietnam; the U.S. is ranked 10th. Within the U.S., Arkansas accounts for the largest share of rice cultivation, followed by California, Louisiana, Mississippi, Missouri, and Texas.

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Description

is extensively cultivated wherever there is enough water, up to an altitude of c. 2000 m. The chief crop is in Kashmir (Liddar Valley). Tateoka reports that this species is native in India and Indo-China but cultivated throughout the warmer parts of southern Europe, Africa, Asia, Australia and Central and South America. There are numerous cultivars of Rice, their most extensive taxonomic treatment being that of Porteres in J. Agric. trop. 3: 341, 541, 627, 821. 1956.

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Wikipedia

Oryza sativa

Oryza sativa, commonly known as Asian rice, is the plant species most commonly referred to in English as rice. Oryza sativa is a cereal with a genome consisting of 430Mb across 12 chromosomes. It is renowned for being easy to genetically modify, and is a model organism for cereal biology.

Oryza sativa contains two major subspecies: the sticky, short grained japonica or sinica variety, and the nonsticky, long-grained indica variety. Japonica varieties are usually cultivated in dry fields, in temperate East Asia, upland areas of Southeast Asia and high elevations in South Asia, while indica varieties are mainly lowland rices, grown mostly submerged, throughout tropical Asia. Rice is known to come in a variety of colors, including: white rice, brown rice, black rice, purple rice, and red rice.[1] Black rice (also known as purple rice) is a range of rice types, some of which are glutinous rice. Varieties include but are not limited to Indonesian black rice and Thai jasmine black rice.

A third subspecies, which is broad-grained and thrives under tropical conditions, was identified based on morphology and initially called javanica, but is now known as tropical japonica. Examples of this variety include the medium grain 'Tinawon' and 'Unoy' cultivars, which are grown in the high-elevation rice terraces of the Cordillera Mountains of northern Luzon, Philippines.[2]

There have been plenty of debates on the origins of the domesticated rice. In 2011, genetic evidence published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS) shows that all forms of Asian rice, both indica and japonica, spring from a single domestication that occurred 8,200–13,500 years ago in China of the wild rice Oryza rufipogon.[6] A 2012 study published in Nature, through a map of rice genome variation, indicated that the domestication of rice occurred in the Pearl River valley region of China. From East Asia, rice was spread to South and Southeast Asia.[7] Before this research, the commonly accepted view, based on archaeological evidence, is that rice was first domesticated in the region of the Yangtze River valley in China.[8][9]

The precise date of the first domestication is unknown, but depending on the molecular clock estimate used by the scientists, the date is estimated to be 8,200 to 13,500 years ago. This is consistent with known archaeological data on the subject.[10]

An older theory, based on one chloroplast and two nuclear gene regions, Londo et al. (2006) had proposed that Oryza sativa rice was domesticated at least twice—indica in eastern India, Myanmar and Thailand; and japonica in southern China and Vietnam—though they concede that there is archaeological and genetic evidence for a single domestication of rice in the lowlands of China.[11]

Because the functional allele for nonshattering, the critical indicator of domestication in grains, as well as five other single-nucleotide polymorphisms, is identical in both indica and japonica, Vaughan et al. (2008) determined there was a single domestication event for Oryza sativa in the region of the Yangtze river valley.[12]

Rice appears to have been used by the early Neolithic populations of Lijiacun and Yunchanyan.[13] Evidence of possible rice cultivation in China from c. 11,500 BP has been found, however it is still questioned whether the rice was indeed being cultivated, or instead being gathered as wild rice.[14] Bruce Smith, an archaeologist at the Smithsonian Institution in Washington, D.C., who has written on the origins of agriculture, says that evidence has been mounting that the Yangtze was probably the site of the earliest rice cultivation.[15]

Zhao (1998) argues that collection of wild rice in the Late Pleistocene had, by 6400 BC, led to the use of primarily domesticated rice.[16] Morphological studies of rice phytoliths from the Diaotonghuan archaeological site clearly show the transition from the collection of wild rice to the cultivation of domesticated rice. The large number of wild rice phytoliths at the Diaotonghuan level dating from 12,000–11,000 BP indicates that wild rice collection was part of the local means of subsistence. Changes in the morphology of Diaotonghuan phytoliths dating from 10,000–8,000 BP show that rice had by this time been domesticated.[17] Analysis of Chinese rice residues from Pengtoushan, which were carbon 14 dated to 8200–7800 BCE, show that rice had been domesticated by this time.[18]

In 1998, Crawford and Shen reported the earliest of 14 AMS or radiocarbon dates on rice from at least nine Early to Middle Neolithic sites is no older than 7000 BC, that rice from the Hemudu and Luojiajiao sites indicates that rice domestication likely began before 5000 BC, but that most sites in China from which rice remains have been recovered are younger than 5000 BC.[13]

Wild Oryza rice appeared in the Belan and Ganges valley regions of northern India as early as 4530 BC and 5440 BC, respectively,[19] although many believe it may have appeared earlier. The Encyclopædia Britannica—on the subject of the first certain cultivated rice—holds that:[20]

Many cultures have evidence of early rice cultivation, including China, India, and the civilizations of Southeast Asia. However, the earliest archaeological evidence comes from central and eastern China and dates to 7000–5000 BC.

Denis J. Murphy (2007) further details the spread of cultivated rice from India into Southeast Asia:[21]

Several wild cereals, including rice, grew in the Vindhyan Hills, and rice cultivation, at sites such as Chopani-Mando and Mahagara, may have been underway as early as 7000 BP. The relative isolation of this area and the early development of rice farming imply that it was developed indigenously.

Chopani-Mando and Mahagara are located on the upper reaches of the Ganges drainage system, and it is likely that migrants from this area spread rice farming down the Ganges valley into the fertile plains of Bengal, and beyond into south-east Asia.

According to Zohary and Hopf (2000, p. 91), O. sativa was recovered from a grave at Susa in Iran (dated to the 1st century AD) at one end of the ancient world, while at the same time rice was grown in the Po valley in Italy. In northern Iran, in Gilan province, many indica rice cultivars including Gerdeh, Hashemi, Hasani, and Gharib have been bred by farmers.[5]

Mainstream archaeological evidence derived from palaeoethnobotanical investigations indicate dry-land rice was introduced to Korea and Japan some time between 3500 and 1200 BC. The cultivation of rice in Korea and Japan during that time occurred on a small-scale, fields were impermanent plots, and evidence shows that in some cases domesticated and wild grains were planted together. The technological, subsistence, and social impact of rice and grain cultivation is not evident in archaeological data until after 1500 BC. For example, intensive wet-paddy rice agriculture was introduced into Korea shortly before or during the Middle Mumun Pottery Period (c. 850–550 BC) and reached Japan by the final Jōmon or initial Yayoi periods c. 300 BC.[13][23]

In 2003, Korean archaeologists alleged they discovered burnt grains of domesticated rice in Soro-ri, Korea, which dated to 13,000 BC. These predate the oldest grains in China, which were dated to 10,000 BC, and potentially challenge the mainstream explanation that domesticated rice originated in China.[24] The findings were received by academia with strong skepticism, and the results and their publicizing has been cited as being driven by a combination of nationalist and regional interests.[25]

Rice is the staple for all classes in contemporary Southeast Asia, from Myanmar to Indonesia. In Indonesia, evidence of wild Oryza rice on the island of Sulawesi dates from 3000 BCE. The evidence for the earliest cultivation, however, comes from eighth-century stone inscriptions from Java, which show kings levied taxes in rice. Divisions of labor between men, women, and animals that are still in place in Indonesian rice cultivation, can be seen carved into the ninth-century Prambanan temples in Central Java. In the 16th century, Europeans visiting the Indonesian islands saw rice as a new prestige food served to the aristocracy during ceremonies and feasts. Rice production in Indonesian history is linked to the development of iron tools and the domestication of water buffalo for cultivation of fields and manure for fertilizer. Once covered in dense forest, much of the Indonesian landscape has been gradually cleared for permanent fields and settlements as rice cultivation developed over the last 1500 years.[26]

In the Philippines, the greatest evidence of rice cultivation since ancient times can be found in the Cordillera Mountain Range of Luzon in the provinces of Apayao, Benguet, Mountain Province and Ifugao. The Banaue Rice Terraces (Tagalog: Hagdan-hagdang Palayan ng Banaue) are 2,000 to 3,000-year-old terraces that were carved into the mountains by ancestors of the Batad indigenous people. It is commonly thought that the terraces were built with minimal equipment, largely by hand. The terraces are located approximately 1,500 meters (5,000 ft) above sea level and cover 10,360 square kilometers (about 4,000 square miles) of mountainside. They are fed by an ancient irrigation system from the rainforests above the terraces. It is said that if the steps are put end to end it would encircle half the globe. The Rice Terraces (a UNESCO World Heritage Site) are commonly referred to by Filipinos as the "Eighth Wonder of the World".

Evidence of wet rice cultivation as early as 2200 BC has been discovered at both Ban Chiang and Ban Prasat in Thailand.

By the 19th century, encroaching European expansionism in the area increased rice production in much of Southeast Asia, and Thailand, then known as Siam. British Burma became the world's largest exporter of rice, from the turn of the 20th century to the 1970s, when neighbouring Thailand exceeded Burma.

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Japanese rice

Japanese rice refers to a number of short-grain cultivars of Japonica rice which are grown in Japan. The two main categories of Japanese rice are ordinary rice (uruchimai) and glutinous rice (mochigome).

Ordinary Japanese rice, or uruchimai (粳米), is the type most commonly grown, and is the staple foodstuff of the Japanese diet. It consists of short translucent grains. When cooked it has a somewhat sticky texture such that it can easily be picked up and eaten with chopsticks. Outside of Japan it is sometimes labeled as sushi rice, as this is one of its common uses. It is also used to produce sake.

Glutinous rice, known in Japan as mochigome (もち米), is used for making mochi (餅) and special dishes such as sekihan. It is a short-grain rice, and can be distinguished from uruchimai by its particularly short, round and opaque grains, its greater stickiness when cooked, and by its markedly firmer and chewier texture when consumed.

Contents

Cultivation

Contemporary cultivation of rice in Japan is highly mechanized, and almost all planting and harvesting is done by machine. The rice seeds are first soaked in water and planted in trays under covers, prior to being planted outside when they have become big enough. Rice fields cover many hillsides in rural Japan. Farmland is limited because so much of the country is mountainous.

Cultivars

Rice is an important crop throughout Japan. Koshihikari (コシヒカリ) is a particularly esteemed cultivar and one of the most highly grown in Japan. Akitakomachi is also quite popular. Sasanishiki is a cultivar known for keeping the same taste when cooled down. Yamada Nishiki is the most famous cultivar grown specifically for sake.

In Hokkaidō, Japan's northernmost prefecture, hardier cultivars such as Oborozuki and Yumepirika have been developed to withstand the colder climate.

Calrose is the name used originally for a medium-grain Japonica cultivar developed in 1948, and now as a generic term for California medium grain Japonicas. While not true Japanese rice, Calrose-type rice has been grown by Japanese American producers in California for many years. It is commonly used to prepare Japanese cuisine in North America, and is reasonably good as a sushi rice. It is also exported to a number of countries including Japan, although it has not gained much popularity with Japanese consumers. In recent years, Koshihikari rice is also being grown in the U.S. and Australia.

Processing

Rice begins as brown rice, genmai (玄米), which may then be polished by a machine (精米機seimaiki), in which case it is sold as ready-polished or white rice, hakumai (白米). Most rice in Japan is processed and consumed as white rice, the staple food of Japan. Brown rice is also consumed in its unpolished state, often for its health benefits, but it is considered a specialty.

Hatsuga genmai (発芽玄米) is brown rice that has been soaked in heated water until germinated. It is also known as GABA rice, as the germination process greatly increases its gamma-Aminobutyric acid content. It has a softer texture than ordinary brown rice and a pleasant fragrance. It is sold in Japanese supermarkets, but it can also be made at home. Some high-end rice cookers have a GABA rice setting to automate the process.

Haigamai is rice that has been partially milled to remove most of the bran but leave the germ intact. It takes less time to cook than brown rice but retains more of the vitamins than white rice.

Coin-operated automated rice polishing machines, called seimaijo (精米所), for polishing brown rice, are a common sight in rural Japan. The rice polishing machines typically polish a 10 kg amount for 100 yen. The by-product of the polishing process, rice bran (米ぬかkomenuka) is used commercially as the source of rice bran oil. It may also be used for making a kind of pickle called nukazuke (ぬかづけ), as an organic fertilizer, and in livestock feed.

Most supermarkets in Japan sell ready-polished rice in 10 kg, 5 kg, and smaller bags. Brown rice is usually sold in 30 kg bags, which may be generally polished by the consumer in a coin operated polishing machine, or in smaller bags in supermarkets intended for eating as brown rice.

Uses

Ordinary rice, or uruchimai, is eaten in several ways in Japan, most commonly as plain rice "gohan"(ご飯?, lit. "cooked rice" or "meal of any sort") consumed as part of a typical washoku meal, with the accompaniment of several okazu dishes (おかず), tsukemono (various pickles), and miso soup. In bento boxes it is often served with a topping of furikake (ふりかけ), a single umeboshi, or a sheet of nori (海苔). It is used in sushi (寿司) and onigiri.

A very simple breakfast dish, tamago kake gohan, consists simply of plain rice mixed with a raw egg, and perhaps soy sauce. It is also common to eat plain rice with the accompaniment of natto, also popular for breakfast, although considered by some an acquired taste. Plain rice is used in yōshoku dishes such as curry rice, omurice, and doria. Leftover plain rice is often reused as ochazuke (茶漬け) (rice with green tea) or chāhan (チャーハン) (fried rice).

Takikomi gohan is made with ordinary rice which is cooked together with vegetables, meat, or fish seasoned with dashi and soy sauce.

Preparation

Most Japanese use suihanki (rice cookers) to which measured amounts of washed rice and water are added. The rice is first washed to release excess starch. Then, before cooking it is usually soaked in water for a time between half an hour in summer, and two hours in winter. Soaking times depend on the quality and freshness of the rice, as well as on the season. The rice is then boiled using a ratio of about five parts of water to four parts of rice – though with fresher rice, the ratio can go down to 1-to-1. After this, it is steamed until the centre of the rice becomes soft. Salt is not added to the rice.

Traditionally, rice was eaten at every meal in Japan; most modern rice cookers can be set ahead by a timer, so that rice will be ready for the morning meal. The rice cooker can also keep rice moist and warm. Rice kept warm like this remains edible for several hours, so that rice need be made only once per day.

Prepared rice is usually served from the rice cooker into a chawan, or rice bowl.

After cooking, rice may also be held in a covered wooden box called an ohitsu.

Trading

The Dojima Rice Market in Osaka was the first known futures market, with trading in rice contracts established sometime around 1730. This market ceased with economic controls in 1939. In 2005, the Tokyo Grain Exchange announced that it would create a futures contract on rice with trading starting in the summer of 2006. [1] However, the trading of these futures contracts has been postponed to an unspecified date since it has not been approved by the Japanese government. [2]

The Tokyo Grain Exchange was founded in 1952 in the same location as the Kakigaracho Rice Trading Exchange, established in 1874. [3] As of 2005, two varieties of Japanese rice were in consideration for standardization of the contract.

In order to fulfill self-sufficiency goals in Japan and to support domestic rice producers, the Japanese government enforces quotas and high tariffs on foreign rice. As a result, most rice consumed in Japan is domestically produced. However, price increases in recent years have led a small but increasing number of Japanese consumers and restaurants to seek out the small amount of less-expensive rice imported from China, Australia, and the United States that is available in Japan.[1]

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Comments

This is the staple cereal rice, widely cultivated in tropical and warm-temperate parts of the world, and with many different cultivated races. It has the AA genome, and where Oryza rufipogon occurs as a weed in rice fields, intermediates may occur.